Legend:

To check on the right coordinates of OS active stations, see the link below

2

4

http://gps.ordnancesurvey.co.uk/active.asp

3

4

5

5

6

Base station data not 1 second resolution? Resample (interpolate using posgps). While this doesn't improve the data, it apparently makes it more evenly applied (no internal interpolation?). Unverified.